High frequency antenna termination unit for aircraft



June. 30, 1970 y R. wgcsowr-:LL :TAL 3,518,682

HIGH FREQUENCY-ANTENNA TERMINATION UNET FOR AIRCRAFT4 Filed June 1v, 1968 TIE. 2

Unid states Patent office 3,518,682 Patented June 30, 1970 U.S. Cl. 343-705 5 Claims ABSTRACT 0F THE DISCLOSURE A wire antenna termination unit having a cylindricallyshaped resistor mounted between two end pieces which are connected 4by means of a dielectric rod passing through the cylinder; the end pieces are provided with spring iingers for providing electrical contact and holding the resistor in place and covers prevent electrical discharge into the atmosphere.

BACKGROUND OF THE INVENTION This invention relates generally to an antenna terminating unit and more specifically to a high-frequency, high-power antenna terminating -unit of aerodynamic design to be used externally of high speed, high altitude aircraft.

:In general, most aircraft today use tuned antennas where the resistance is manually varied depending on the frequency. In this case, the need for an energy-dissipating means on the antenna wire is done away with. However, these antennas are limited in their frequency range in that it may become impractical to tune antennas over a 'wide frequency range. There is, therefore, in some cases, the need for untuned antennas. In these cases, excess energy must be dissipated in the form of a resistor located along the antenna wire and preferably at the end. When frequencies are low and power is 10W, a plurality of conventional resistors mounted in a small, bullet-shaped container would provide no problem either electrically` or mechanically. Devices of this nature may utilize a number of conventional resistive units soldered together internally of an outside shell. In this case, the energy dissipated and the heat caused by such energy dissipation creates no serious problems. Similarly, the outside covering is small enough that it Iwill not cause substantial aerodynamic drag nor rwill it require the antenna wire to be unduly large to hold the shell in place in speeds in the order of 600 mph. However, when high frequencies are used at high power, for example in a traveling wave transmitting antenna operating in the 1 mHz. to 60 mHz. frequency range, heat buildup would require a resistance of such substantial proportions that it would be impractical, .if not impossible, to use an enlarged version of the prior art. With the terminating unit of the instant invention the aforementioned defects are overcome.

SUMMARY OF THE INVENTION This invention provides a silicon glass resistor incorporated into a novel holder designed to form a stable, 10W reactance antenna termination unit.

The holder design of this invention permits the termination unit to be used directly with standard antenna hardware and requires no modiiication to the aircraft in which it is installed. Further, this invention forms a continuation of the antenna in that it is generally a long cylinder of small diameter not substantially greated than the wire itself. The antenna termination unit will easily dissipate 500 watts of radiant energy power into the ambient air when in normal use. Furthermore, the instant invention provides no strain whatsoever on the resistive component of the antenna termination unit. In its essence this invention comprises a phenolic rod threaded at each end with means at one end for attaching it to the aircraft, and means at the other end for attaching it to the antenna lwire. A resistor is mounted concentrically around the rod and insulated therefrom. The antenna wire is in a conducting relationship with the resistor.

It is therefore an object of this invention to provide a new and improved antenna termination unit for use with aircraft antennas. Y

It is a further object of this invention to provide a new and improved antenna termination unit in rwhich drag and air turbulence is minimized.

It is another object of this invention to provide a new and improved antenna termination unit which has higherpowered dissipation than any hitherto known.

It is still a further object of this invention to provide a high frequency antenna termination unit which has low reactance comparison to volume and cross section.

It is another object of this invention to provide a high frequency antenna termination unit for aircraft in which all contact surfaces are totally enclosed, thereby eliminating air stream erosion and reducing the possibility of corona discharge.

Another object of this invention is to provide a high frequency antenna termination unit for high speed aircraft which does not require a resistive unit to contribute any mechanical support to the antenna wire and yet provides a resistive termination directly to the end of the wire.

IIt is another object of this invention to provide a new and improved high frequency antenna termination unit which is economical to produce and utilizes conventional currently available components that lend themselves to standard mass production manufacturing techniques.

These and other advantages, features and objectives of the invention will become more apparent from the following description taken in connection with the illustrative embodiment in the accompanying drawings, wherein:

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view in section of a preferred embodiment of the invention; and

FIG. 2 is an enlarged cross-sectional view taken along lines 2 2 of FIG. 1 of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown generally the antenna termination unit 10. An antenna wire 12 of any conventional aircraft type enters the termination unit through a hard rubber boot 14 which mates into an end piece 16 `which is in turn secured to the jaw housing 18. Contained within the jaw housing 18 are a pair of jaws 20 which clamp the antenna wire 12 securely by means of the tapered sides of the jaw housing 18. A phenolic rod 22 threadably engages the jaw housing 18 and is connected to an end piece 24 which is in turn connected to a standard antenna mount on the aircraft.

Surrounding phenolic rod 22 is a resistor 26 which may be of a known silicon-glass type. The resistor is held in place at each end and insulated from the phenolic rod by O-rings 28 and 30. Spring fingers 32 and 34 1ocated at opposite ends of the resistor and formed from part of the jaw housing and end pieces respectively, surround the resistor at a point directly opposite from the O-rings and apply a securing force against the resistor as will be described hereinafter with regard to FIG. 2. Contact spring shells 36 and 38 cover the spring fingers and are secured Iwith a tight sliding fit over the jaw housing and end pieces. The spring shells provide a more perfect aerodynamic shape and avoid any possibility of corona discharge at high altitudes when utilizing high power radio frequency energy on the antenna. The jaw housing 18 and contact ngers 32 provide an electrical contact between the antenna 12 and the resistor 26. Means not shown, connect the end piece 24 to the aircraft and electrically insulate the resistor therefrom. It should be pointed out that all forces exerted on the termination unit by the antenna wire are taken by the phenolic rod and its mounting means. No force in this direction is placed on the resistor unit.

Concerning FIG. 2 which is taken along the lines 2-2 of'FIG. 1, the phenolic rod shown at 40 is surrounded by the rubber O-rings 42. The O-rings are mounted in groove in the phenolic rod (27 and 29 of FIG. 1) and exert a slight outward force against the resistor 44. Fingers 46 which'are formed from the jaw housing or end piece apply a slight inward pressure against the resistor 44, thus the resistor is held securely in place, however allowance is inherent in the design for changes due to temperature or slight vibrations in the termination unit. The contact spring shell 58 surrounds the teeth and, as aforementioned, provides an aerodynamic shape and precludes the possibility of corona discharge into the atmosphere.

Although the invention has been described with reference to a particular embodiment, it is understoodl to those skilled in the art that the invention is capable of a variety of alternative embodiments within the spirit and scope of the appended claims.

What we claim is:

1. A high-frequency aircraft antenna termination unit comprising in combination: an antenna wire; a cylin drically-shaped resistor; means for connecting the antenna Wire and resistor in an electrically conducting relationship; means for securing the antenna to the connecting means; means for securing the resistor to an aircraft; a dielectric rod located internally of said resistor and threadably engaging the connecting means at a first end and threadably engaging the securing means at a second end; a pair of resilient means located near each end of said resistor, between the dielectric rod and the resistor, applying a force against the resistor; a plurality of biased metallic fingers exerting a force against the resistor in the direction opposite from that of said resilient means; 'and means for covering the ngers whereby the unit is provided with a substantially aerodynamic shape.

2. A high-frequency aircraft antenna termination unit according to claim 1 wherein the means for securing the antenna to the connecting means is a tapered wiregripping jaw.

3. A high-frequency aircraft antenna termination unit according to claim 1 wherein the resistor is silicon glass.

4. A high-frequency aircraft antenna termination unit according to claim 1 wherein the dielectric rod is formed of a phenolic material.

5. A high-frequency aircraft antenna termination unit according to claim 1 wherein the resilient means are rubber O-rings.

References Cited UNITED STATES PATENTS 2,790,023 4/ 1957 Keller 343-705 ELI LIEBERMAN, Primary Examiner 

